1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method therefor. More particularly, the present invention relates not only to processing for displaying an image input to, e.g., an image pickup apparatus or an image inputting apparatus, more specifically a digital camera, a video camera, a mobile-phone handset, a scanner or the like, but also to display processing in a recording/reproducing field including a display unit configured to display, e.g., image data recorded in a raw data mode or a printer configured to print images on recording media. Particularly, the present invention relates to automatic display and automatic printing or print service.
2. Description of the Background Art
Various methods have been proposed in the past for correcting an input image in such a manner as to render the image attractive, as will be described hereinafter.
U.S. Pat. No. 4,931,864to Kawamura et al., for example, discloses an image forming apparatus configured to select a particular area of an image and execute gamma correction adequate for the selected area. U.S. Pat. No. 5,715,377 to Fukushima et al., proposes a gradation correcting method and an apparatus therefor configured to correct gradation in accordance with scene information relating to an input image and the degree of brightness.
Fukushima et al., also proposes a gradation correcting apparatus constructed to divide an image into a plurality of blocks, determine whether on not the image is backlit on the basis of luminance information of the blocks, extract a person on the basis of the luminance and color information of skin and then determine the degree of backlight on the basis of the luminance of the extracted person. The apparatus corrects gradation in accordance with the degree of backlight thus determined.
U.S. patent application publication No. 2003/0020974 A1 to Matsushima discloses an image processing apparatus configured to select a candidate area where the saturation of gradation would be conspicuous if the area were subjected to correction, update a gradation correction curve in accordance with information derived from the candidate area and then correct the entire image by using the above curve. This is successful to protect an image from the saturation of gradation ascribable to correction.
U.S. patent application publication No. 2003/0099407 A1 to Matsushima teaches an image processing apparatus constructed to correct contrast in such a manner as protect, e.g., an image representative of a backlit scene or a portrait from the saturation of gradation and hue variation. More specifically, the image processing apparatus taught in Matsushima '407 selects a candidate area where the saturation of gradation would be conspicuous if the area were subjected to contrast correction, sets a dynamic range in accordance with information derived from the candidate area and then corrects the contrast of the entire image by using the dynamic range thus set.
Further, Japanese patent laid-open publication No. 2004-180173 proposes an image pickup apparatus configured to execute gamma correction for softening the gradation of an image in accordance with the detection of a person present in the image, thereby picking up the person's face attractively.
However, a problem with the prior art technologies described above is that scene analysis cannot always correct a backlit scene, which is one of undesirable scenes including a person or persons, to desirable brightness alone. Another problem is that even if a desired person may be accurately detected and corrected to adequate brightness, it is impossible to correct the entire image to adequate brightness at all times.